Cordless switch board



May 21, 1963 sl-n-:l INABA ETAL CORDLESS SWITCH BOARD Filed April l2, .1960

6 Sheets-Sheet '1 WWW@ May 21, 1963 sHEl lNABA ETAL 3,090,839

CORDLESS SWITCH BOARD Filed April 12, 19Go e Sheets-Sheet 2 May 21, 1963 sHl-:r INABA ETAL 3,090,839

CORDLESS SWITCH BOARD Filed April 12, 19Go e sheets-sheet s Figi A EXT May 21, 1963 sHl-:l INABA ETAL 3,090,839

CORDLESS SWITCH BOARD 6 Sheets-Sheet 4 Filed April l2, 1960 AUX wf/M232 May 21, 1963 sHEl INABA ETAL 3,090,839

CORDLESS SWITCH BOARD Filed April l2, 1960 6 SheeS-Shee'b 5 MW 795mg? May 21, 1963 soHEl INABA ETAL 3,090,839

CORDLESS SWITCH BOARD 6 Sheets-Sheet 6 Filed April l2. 1960 3,090,839 CGRDLESS SWTCH EGARD Sche inaba, Tokyo, Shir- Kno, lsezaki-slsi, Gunrna, Wak lwarnura, Tokyo, and Trn Mikami, Kiryu-slli, Gunrna, .apan

Filed Apr. 12, 1969, Ser. No. 21,788 10 Claims. (Cl. 179-91) The present invention relates to a telephone switch board characterized in that it possesses a circuit therein connected to desirable line or lines by relays provided at the cross points of the trunk lines, the extension lines and the subscribers ylines, and including self-restoring mechanisrn, the relays being energized by nonlocking keys which are included in the respective lines.

There are two types of conventional telephone switchboards, the cord type and the cordless type. The cordless type is generally more useful than the cord type because of its relative ease of operation and its attractive appearance. However, the conventional cordless switchboard is provided with such a large number of universal keys that not only is its operation complicated and difficult but ralso the operator tends to make errors in operation. The present invention not only has the advantages of the cordless type, but also reduces the chances of misoperation.

One feature of the present invention is the connection of a circuit utilizing simultaneously energized quick acting and slow acting relays in association with other relays which are restored by opening their holding circuits, by operating the quick acting relay during the time delay period of the slow acting relay.

Another feature ofthe invention is that the hook switch of the switchboard is interlocked with switches :for the working and holding circuits to prevent ruis-operation by the operator but, in turn, preventing a change of connections unless the operators hand set is hung on the hook.

A further `feature of the invention lis that a busy signal lamp is operated by Va key included in a subscribers line Kand also eect-ive to pick up connecting relays at crossing points of the subscribers line, extension lines, and trunk lines. The operator is able to detect the service condition of a line by flicking the busy signal `lamp in an extension or trunk line connected to the subscribers line. Also, the operator can test the service condition of `all the extension or trunk lines connected to the subscribers line.

A further feature of the invention is that an automatic selection of a free subscribers Kline may be made by operating a non-locking key in extension or trunk lines, with the subscribers `line lbeing provided with self-restoring relays.

A further feature of the invention is that an audible signal is provided if all of the subscribers lines are busy.

As a further feature, the condition of telephones connected directly to the trunk lines may be determined by busy signal larnps, each of the lines having a relay which is energized by current transmitted to a trunk `line when the operator connects the trunk line to `the telephone by operating .a trunk 4line changing key. Also, Awhen extension ylines can be connected directly to a trunk line.

A particularly `advantageous feature of the invention is that a clearing signal is transmitted to each trunk line as soon as the line is clear, the clearing signal being provided by the mentioned combination of quick acting and slow acting restoring relays. usually required with a switchboard is provided by a transistorized oscillator, the oscillator not interfering with any of the circuits of the switchboard.

Gther advantages of the invention will become apparent from the description hereinafter shown |by way of examples in the accompany-ing drawings. ln these draw- Preferably, the audible signa-l i ing: FIG. l is `a schematic electrical diagram illustrating the principles of the present invention; FIG. 2, FIG. 3, FiG. 4 and FiG. 5 show respective embodiments of the present invention; FIG. 6 is a perspective view of the asseinbled'push `button Iaccording to the invention; and FlG. 7 is an exploded perspective view of the disassembled parts ofthe push button.

Referring to the drawings, in FlG. 1 nomenclature is as follows; TRKI, TRK2, are trunk hues; EXT1, EXT2, extension lines; CONl, GONZ, subscribers lines; OP operator line; TK nonlocking key to control the trunk line; EK nonlocking key to control the extension line; CK nonlocking key to control the subscribers line; TC1 1, TC1 2, EC2 1, EC2 2, self-restoring relays provided for connecting the trunk lines or the extension lines to the subscribers lines respectively; TF1, "FP2, self restoring relays provided for connecting the operators line to the trunk lines; EF1, BP2, self-restoring relays provided `for connecting the extension 4lines to the operators line; T1, T2, self-restoring relays provided for connecting the operators line to the subscribers lines; TBLl, TBL2, busy signal lamps of the trunk lines; CBL, OBL2, busy signal lamps of the subscribers lines; respectively.

in the conventional cordless switch board, the switches corresponding to TK, EK and CK are not provided, but keys are provided at the cross points of respective lines, i.e. at the locations of relays TC, EC, TP, EP and T in PEG. i. These keys must be operated lby hand to change connections, `and after clearing the line, have to be operated again by hand to restore the line to service. According to the present invention, the keys provided at each cross point of the lines are replaced by restoring relays which are operated by non-locking keys supplied in the trunk lines, extension lines, and subscribers lines, respectively, although the switchboard does not thereby lose its capability. These relays effect automatic restoring after the call is completed. Only one non-locking key is used in each line, so as to reduce the number of keys. Generally, in switchboards' when the succeeding operation begins, it is necessary that it is star-ted `after the connections for the preceding operation have been restored. For instance, when an operator answers the call from ran extension line, and after the call is finished, the operator has `to answer successively the calls from other extension lines, then the operator begins to set tup a new connection after restoring the connections by which the first call was completed. ln the case of operations using a non-locking key, the relay is energized by operation thereof, and connection of the line is maintained by holding the relay energized. Therefore, when it is necessary to set up a new connection after restoring a completed previous connection, the relay maintaining such previous connection is restored yto the same condition `as before the previous connection was setup. Restoring `keys are utilized in the relay holding circuits, these keys rendering the holding circuits ineffective. According to the present invention, the usually required Vmanual resetting after the first operation is eliminated and the relay Iwhich holds the first connection is restored automatically even if the second connection 'is made at once, so that operation is clearly simplified,

Furthermore, mis-operation of the switchboard is prevented, l-f the operatior inadvertently touches a key in conventional key, it is cause of anis-operation. ln the invention arrangement, such inadvertent touching of a key is ineffective unless the operator purposely touches a key for the purpose of changing connections. Thus, the operation is made `fool-proof and greater safety against mis-operation is provided. As a result, the switchboard the switch board.

does not have to be installed with any special orientation of the board relative to the operator.

In a conventional switchboard, the operator must charge, by the position of a key, What lines are connected.

ln contra distinction, inthe invention switchboard, such4 checking .may be effected merely by iickering busy signal lamps in extension lines connected to subscribers lines. This is done rnerely by operating a key provided in the respective subscribers lines, so that the connection o-f the board rnay Vlberreadily observed and understood by the operator in a simple manner. Furthermore, in a conventional switchboard, the operator must determine what lines `are not in service before making connection and, after such determination, the operator makes the necessary connections. ln the invention switchboard' a free subscribersline may be automatically selected for connection fwith a trunk or extension line by operating the non-locking key supplied in -the subscribers lines, so that operating eiciency is yenhanced and `accidental mis-connections are avoided.

Iff the subscribers line is busy, a signal is provided when the non-'locking key in the trunk or extension line is operated. In the usual case where the call cornes to the switchboard operator, the latter nonmally connects the trunk Iline to the called telephone or extension by using the trunk line switching key. However, it is not possible for the operator to tell, from the setting of such key, whether or not the called :line is in use. Consequently, if the operator restores the trunk line switch to make a new call, it is possible that a connection still in use may be Vbroken inadvertently. According to the present invention, the operator can detect the service condition of a line by lookin-g lat the switchboard.

In the conventional switchboard, not only must the keys'operated to establish a connection be restored but also a clearing signal must be transmitted to the trunk line by operating a special signal key. In the present invention, such clearing signal is transmitted automatically upon restoring of the connections.

A conventional switchboard is provided with a common circuit for lighting the line lamp and simultaneously ringing a bell or buzzer when the switchboard receives a cal-l from Va trunk or extension line. due to interference with` radio or television equipment. The present invention obviates this by using ya signal lgenerating oscillator.

In a conventional switchboard, the lamps and keys have independent functions, but there is a close relation therebetween which frequently results in lmis-operation. In thevpresent invention, switching is effected by operating a position button which has incorporated therein a lamp lwhich may provide a visible signal of one'or more colors, and the position buttons have the same colors as the lamps.

Now explaining each embodiment according to this invention shown in FIGS. 2, 3, 4 and 5 respectively. The wiring diagram of FIG. 2 will be used for explaining the connecting of the trunk line or the extension line with the subscribers line, as well as the operation of the self-restoring circuit, safety apparatus circuit, service condition discriminating circuit, connection self-selecting circuit, busy alarm circuit therefor and functions of 'n 2, TRKI, EXTl, CONl, CO'N2, OP, TK, EK, CK, TC1 1, TC1 2, EC1 1, EC1 2,

T1, T2, TBL1, EBL1, CBL1 and CBL2, the same com-V ponents as in FIG. l.Y tc1 1, tc1 2, e1 1,rec1 2, t1 and -t2 represent contacts of the relays TG1-1, TC1n2, EC1 1, VEC1 2','T1 and T2 respectively; TLL1 and ELL1 received signal indicating lamps of TRK and EXT respectively;

S1, S2 S1, S2 current Yfeeding relays having their contacts included in the subscribers lines CON1, CON2 respectively and feeding to the extension lines; CC and cck a relay and its contact to prevent the double Vconnection when self-selecting any subscri-bers line which is used as the common circuit; K and k a relay This is undesirable and its contact included in the common circuit to prevent mis-operation; X, W, x and w a quick-acting relay and a slow-acting relay and their contacts used in the common circuit for self-restoring; LK1, LK2, nonlocking keys for establishing connections, these keys being included in the respective subscribers line CON1, CON2, :RLS1, RLS2, nonlocking keys for breaking connections, these keys being also included in the respective subscribers line CON1, CON2, ORS nonlocking key .for breaking the connection making the operator line a common circuit with each line. AUX is a sound generating circuit for providing a receiving signal, wherein, in the drawng, Z2, z1, Z2, z2 and -BZ are self-rectoring relays, these relays being operated when a signal is received, energizing their contacts and buzzer or bell which is sounded when its energizing circuit is closed or is switched on. ZK is a switch 4for cutting Aoff bell or buzzer. TLG is a known trunk line, in which CT and CR are condensers for interrupting direct current and r is a contact which is closed by the relay operated by the signal current from the trunk line when a signal is received from the trunk line. HOOK2 are contacts which are closed by removing the handset from the hook switch. SAF components of a safety circuit for cutting off the circuit at x and connecting it to the part shown in broken lines, when necessary.

If key CK, in the subscribers line is operated by pushing, relay T1 is transferred and is held through 11(1), while t1(.1) and t1(5) are conditioned to connect the subscribers line. Next a switch EK in the extension line, forV example EK1, is pushed and EC1 1, at the crossing of the subscribers and extension line, is transferred through im). EC1 1 is held through ec1 1(1) and the extension line is connected to the subscribers line by C1 1(2) and EC1 1(3). C1 1(4) and C'1 1(5) are @Y0- vided to open the received signal lamp circuit.

The operator calls the extension line in a conventional manner, and after the extension line responds, relay S1 supplies signal transmission current to the extension line by opening the connection between the operators line and the extension line. 81(1) even if T1 is restored and t1(5) opened by ORS. The

w other extension line or trunk line is similarly connectedto the subscribers line Iby releasing T1 by pushing its ORS and completing the connection by switching off the operators line. When the call is terminated, the handset is replaced on the hook or cradle and s1 is restored. This restores E'C1 1 and the extension line. t1(2) and t1@ function to connect the operators line to the subscribers The mechanics of the -hook release for the trunk line and for light flashing are carried out in the known manner. Also, when CK is pushed, quick-acting relay X and slow-acting relay W are energized. Relay X is transferred immediately but relay W is transferred only after a time delay. As relay W is transferred, it restores relay X by opening its energizing circuit. As CK is restored, relay .W is restored.

Thus, if CK2 is pushed while T1 is transferred, T2 is transferred. However, relay X is transferred simultane- Vously and remains transferred until relay W transfers. Consequently, contact X is opened during the time delay ofrelay W so that relay T1 is restored.

Now, if CK2 is held for a time in excess of the time delay of relay W, contact X is restored to bold relay T2.

HOOK1 and Relay EC1 1 is held transferred by The subscribers line cannot `be opened from the eXtension line or the trunk line through RLS unless K is energized to connect k by operating HOOK1. Thus, no change in connections can be made unless the handset is removedv from the hook or cradle. Consequently, changes in connection can be made only purposefully and not inadvertently.

When the subscribers line is connected with the eX- tension line or trunk line by EC or TC, the busy signal lamp EBL or TBL in the extension line or trunk line is lit on account of the circuit provided thereto, the circuit being from the check key LT in the subscribers line through the contact ec) or tcm) as shown in FIG. 2. By bringing down the check key LK in the subscribers lin-e to discriminate the service situation, all the busy signal lamps in the extension lines which are connected to the subscribers lines are ilickered, so that, seeing the said flickering lamps, the operator can easily and perfectly discriminate the service situation of the eX- tension lines or trunk lines. As further shown in FlG. 2, the discriminative circuit is so Wired as to be independent of the communication circuit so that operation o-i check key LK will not interrupt a call. Key CK can be used in place of key LK, if desired;

Therefore, according to the present circuit, the operator can easily and properly check the service situation of all extension `lines or trunk lines connected to the subscribers lines by only observing the busy signal lamps included in the extension line or the trunk line.

lt has been explained previously that, in the case of energizing T in the subscribers line, the trunk lines or extension lines are connected with the subscribers lines by pushing EK or TK. However, when T is not energized `but EK or TK is pushed, then the open contact of T is grounded through the contact s of the relay S `from EK or TK. This relay S is connected to the subscribers line, as shown in FIG. 2, so that, by pushing K or TK, T is energized to hold EC or TC, which are provided for connecting the corresponding subscribers line with the corresponding trunk or extension line therewith. As a result, the said subscribers line is connected with lthe said extension or trunk line.

ln the drawing, CC is an interlock relay to prevent the mis-connection in such a case that, during the time a relay T in a subscribers -line is energized by the contact tw), no other relay T is operated even if the operator pushes EK or TK; cc is its contact and im is a contact of the relay T for interlocking said circuit. Therefore, according to the present circuit the extension line or trunk line is selectively connected to the open contact of the subscrihers line by operating only the nonlocking key controlling thereof.

It all the subscribers lines are busy, the operatormay be alarmed by the belll or buzzer, which is operated by pushingV EK or TK, said EK or TK energizing Z2 through s` and closing z2.

FIG. 3 shows an example of the circuit according to the invention in which the trunk line and the subscribers line are in common, the said circuit including a connecting part of the subscribers line with the extension line, a self-restoring circuit, a safety apparatus circuit, a service situationA discriminative circuit of the trunk and extension lines and also a service-situation-discriminative circuit of the direct telephones in the subscriber-s line.

TRK, EXT, OP, EK, EC, T and BBL designate the same parts as in FiGS. l and 2, and ELL, S, s, K, k, X, W, x, w, RLS, ORS, AUX, BZ, ZK, HOOK1 and HOOK2 designate the same parts as in FTG. 2.

TK is a nonlocking key by which the trunk line and the subscribers line is controlled, this key corresponding to TK and CK in FIGS. l and 2, and having a function `of LK also in FIG. 2; T a self-restoring relay corresponding to T and TP in FIGS. l and 2; t a contact of T; CV a Seli-restoring relay corresponding to EC in FIG. l;

and FIG. 2; c a contact of C; KK a trunk line changing key; T1 and R1 a couple of terminals for changing the trunk line and to which the telephone directed to the trunk line is connected by switching on the trunk line changing key; T2 and R2 a couple of terminals for changing the trunk line and to which the terminals of the extension line are connected in the case that the telephone is lused as an extension set, when the said telephone directed to the trunk line by switching on the trunk linechanging-key is disconnected from the trunk line, i.e. the trunk line changing key switches oi the line; R a signal -current receiving relay; r a contact of R; CT and CR condensers lfor interrupting direct current; g a contact for consisting of a direct current loop in the trunk line as known; U a relay operated by the current through the trunk line on account of the constitution of the direct current loop in the trunk line; u a contact operated by U.

ln FIG. 3, detailed explanation is omitted, because it is as same as in the case of FRG. 2. Thus, it isinecessary for connection or disconnection to operate K byclosing HOOK1 or HOOK2. The line is connected by pushing TK rst and CK second to operate relay C which is provided at the cross point of TRK and EXT. After the communication is iinished when the operator line has been disconnected already, the line is automatically restored by means of putting the handset on the hook switch of the extension telephone in the extension line, and that in the case of holding the operation of one of the relays T by pushing one of the switches TK, if another switoh TK is pushed in the case of the aforesaid condition, then the initially operated relay T is restored and only a second relay T is energized -by pushing a second switch TK.

InV FTC'. 3, the trunk line TRK is directed to the telephone connected to T1R1 by switching on the direct-extension change-over key KK so as to close KKQ), KK@ and KKH). Then, the telephone, having been directed to the trunk line may, be connected with the trunk line by way of CR. However direct current tlows through the relay U, so that the relay U is energized by the local battery. Therefore, TBL is -lit by the closing of contact u, through KK), so that the operator can observe from the switch board that this direct line is just inservice. KKH) is a contact with which T is interlocked if TK is operated in the case that the associated line is so connected. KK@ is a contact for changing-over the busy signal and the service signal, the former being for observation of the service situation of the trunk line TRK at the switch board in the case that TBL is used in the ltrunk line, the latter being for discrimination of the direct line in the case of connecting the trunk line into the direct line.

If the extension line is used vas the direct linel in the foregoing example, the result is that terminals T2 and R2 are connected to the extension line as` shown in FIG. 3, as, normally, T1 and T2, and R1 and R2 are connected ith KKQ) and KKQ), respectively.

FIG. 4 shows a relay circuit for transmitting the clearing signal, and corresponds to part ofV the trunk circuit and subscribers circuit shown in FIGS. 1, 2- and 3. In FIG. 4, TRK is the trunk line, as in FTGS. l, 2 and 3; S and s the same as in FTGS. 2 and 3; H and h a quickacting relay and its contact operated by a; N and n a time-lag restoring relay and its contact operated fby' h; -M- and m sometimes a quick-acting or otherwise a timelag restoring relay and with its contact operated interlocked -by operation depending on n or h.

Now, when the trunk line is connectedr with the extension line, the extension telephone is connected to the subscribers line, so that when the circuitl is closed by the extension telephone, S is energized and N, H are transferred sequentially. After clearing the line, S isV restored by hanging the handset of the extension telephone on the hook switch, so that H is also restored, hu) is opened, and ha) is closed to transfer N. However, N is notY restored Ved thereon.

at once butonly a preselected delay time after h is opened, because N is a drop-time-delay relay. Therefore, during this time lag, M is still energized because n and hm) are closed and the operation circuit of M is still maintained. When N is restored, then M is restored on account of opening the transfer circuit of M at n. That is to say M is still energized during the time delay provided by N after the communication is completed. Therefore the clearingV signal is transmitted to the trunk line in such a way that the signal current is prepared in the known circuit by the operation of mu) during the time delay, and the signal current flows to the trunk line through mm) and m). Moreover, if M is slow-acting restoring relay, then the time interval of the clearing signal is as long as the summation of the time-lags of N and M. AIt is Very effective for practical use to have a fairly long time of signaling.

FIG. 5 shows a sound generating circuit corresponding to the AUX part in FIGS. 2 and 3, and wherein a tran-V sistor is used.

In FIG. 5, TLL and ELL are the same as in FIGS. 2 and 3; r the same as in FIGS. 2 and 3; TEL an extension telephone wherein the handset is hung on the hook switch, and showing the contact Ht thereof opened; Rt an internal impedance. In the AUX part Tr is a transistor; R1, RZ, R3 and r1 resistors; C a condenser; M a transformer; REC a receiver; Eb base voltage. In FIG. 5, if the circuit receives the signal from the trunk line, r is closed, and the contact Ht of the hook switch of TEL is closed by taking oif the Vhandset of the extension telephone therefrom. OnV account of these closed contacts, oscillations are developed by the operation of the transistor soV that the tone of REC alarms the operator. This circuit is a blocking oscillator circuit in which the base voltage Eb is equal to in the state that r or Ht is opened and the transistor is in a state of OFF. However, if the contact r or Ht is closed on account of the call from the trunk line or extension line, then Eb becomes negative and the transistor oscillates to operate REC. This oscillating frequency can be so easily adjustable that any kind of the sound lwhich the user of the switch board desires can be generated. Also, in this case, the handset of the operator can be used as REC.

`In FIGS. 6 and 7, the push button 1 which is made from semi-transparent synthetic resin or glass is mounted on the shaft 2 which is rotatably supported in the top part of the frame 3. The push button is always pressed` upwardly by the spring 4 which embraces the shaft 2.

One end of the plate spring 5 is in spring contact withV a part of the push button, and another and thereof is mounted on the frame. upward movement of the push button to a certain height, the push button being pushed upwardly by the spring 4. The `spring 5 is so arranged that the push button can be pushed down without any trouble. However, the push This spring 5 can restrict the' held by the spring 6 so as not to drop from the lamp `-12 lwhen `the push button 1 is in the inclined position.

Now, explaining its operation, the push button 1 is operated to switch the desired contacts and to Vlight the associated lamp 12 by pushing down the key which isY at a certain height, the lamp indicating the condition of.

the operation thereof. Push button .1 is returned to its original position when manual pressure is released. When lampV 12 is lit, push button y1 is completely illuminated due to its transparent body, so that the operator can readily observe its operating condition. If a combination of several sets of switch contacts is used, respectively different colored lamps 12 or caps 13 are used for each set for ready visual determination of the operating conditions of the respective sets by observation of the color of the illumination of the push button.

Lamps 12 can be easily exchanged by hand if the push button is removed from the frame by pressing it upwardly. Therefore, in contrast with conventional push button assemblies, it is unnecessary to remove the other parts of the push button assembly for exchanging the lamp thereof, so that the present invention is very useful for maintenance of the equipment itself.

The present invention performs the function of the ordinary key by means of operating the push button, and the operator can discriminate clearly the operating condition by observing the colored light on the push button in accordance with the lighted lamp or lamps included therein.

For instance, according to the invention, the operator can easily distinguish a lighted key from the other` keys when a particular key is operated as the lamp in the operated key is lighted as a call sign. As another example, the operator can easily observe that a key must not be operated when a certain colored lamp is lighted, such color meaning that the line is busy, so that there is no chance of mis-operation. As a further example, in the Acase that a lamp is flickered as a result of an operation of a'key, the operator can :discriminate it from other lighted keys lso as to be certain -which key has been operated. Therefore, the present invention provides a button l1 can be easily removed from the frame 3 if it is taken out upwardly against the pressure of the spring 5. 'Ihe lever 7 which is rotatably supported on the frame 3 is rotated on the shaft 8 by means of the roller 18 which is pressed by pushing the push button 1 downwardly.

The contact plate springs 1=1 are operated by pressingY the spacer 9 which is in immediate contact with one end of the armed lever 7 by way of the adjusting piece mount- The reference numeral 17 designates the bushings in which the pin 8 is supported. The contact plate springs 11 can be a suitablercombination of springs depending on the object of use, as well as the materials of the known universal key or relay.

The lamps 12 are engaged in sockets 13 held by the insulated plate 14 and the holding plate y15 or the like. When the lamps 12 are lit, the respective'color of the light therefrom can be changed by changing the color cap 16 by which each lamp 12 is covered if Yit is necessary, so that the operator can know what kind of lamp is lit, in the c ase of using more than two lamps. Each color cap is very useful push button assembly for its faultless operation, as compared to `faulty misoperations which may occur in the case of using independent bodies of lamps and keys as known in the conventional manner.

Y As the foregoing description will make clear to anybody skilled in the art, the invention can be carried out within the scope of the claims hereinafter.

Having thus described the invention, what is claimed Y as new and'desired to be secured by Letters Patent is:

- l. In a cordless telephone switchboard for interconnecting selected first lines to selected second lines, and including an operators line; a plurality'of self locking operators line connecting relays each operable when energized,`

to connect a respective associated first line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated rst line to its associated second line; normally open fir-st push button switches each associated with a different first line and each effective, when selectively momentarily manually closed, to energize the associated operators line connection relay; normally open second push button switches each associated with a dilerent second line and each effective, when selectively momentarily-manually closed, to energize the particular associated second hold relay associated with a rst line then having itsY associated rst hold relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connecting relays and energized immediately upon closure of a first push button switch, to open said locking circuit; and a slow transfer relay in said operators line energized simultaneously with said quick transfer relay, by closure of a first push button switch;

said slow transfer relay normally completing a locking circuit for said quick transfer relay and, when transferred, opening said last-named locking circuit to restore said quick transfer relay to restore said first-mentioned locking circuits.

2. In a cordless telephone switchboard for interconnecting selected first lines to selected second lines, and including an operators line; a plurality of self locking operators line connecting relays each operable when energized, to connect a respective associated first line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated first line to its associated second line; normally open first push button switches each associated with a different first line andv each effective, when selectively momentarily manually closed, to energize the associated operators line connection relay; normally open second push button switches each associated with a different second line and each effective, when selectively momentarily manually closed, to energize the particular associated second hold relay associated with a first line then having its associated first hold relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connection relays and energized immediately upon closure of a first push button switch, to open said locking circuits; and a normally closed hook switch in said operators line closed when the operators handset is removed from the hook and controlling the energizing circuits of said operators line connecting relays.

3. In a cordless telephone switchboard for interconnecting selected first lines to selected second lines, and including an operators line; a plurality of self locking operators line connecting relays each operable when energized, to connect a respective associated rst line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated first line to its associated second line; normally open first push button switches each associated with a different first line and each effective, when selectively momentarily manually closed, to energize the associated operators line connection relay; normally open second push button switches each associated with a different second line and each effective, when selectively momentarily manually closed, to energize the particular associated line interconnection relay associated with a first line then having its associated operators line connection relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connecting relays and energized immediately upon closure of a first push -button switch, to open said locking circuits; busy signal lamps in each of said second lines; and an energizing circuit for each busy signal lamp including, in series, a transferred contact of the associated line interconnection relay and a manually operable checking switch associated Iwith each first line.

4. In a cordless telephone switchboard for interconnecting selected first lines to selected second lines, and including an operators line; a plurality of self locking operators line connecting relays each operable when energized, to connect a respective associated rst line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated first line to its associated second line; normally open first push button switches each associated with a different first line and each effective, when selectively momentarily manually closed, to energize the associated operators line connection relay; normally open second push button switches each associated with a different l@ second line and each effective, when selectively momentarily manually closed, to energize the particular associated line interconnection relay associated with a first line then having its associated operators line connectionV relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connecting relays and energized immediately upon closure of a first push button switch to open said locking circuits; and a plurality of signal relays each in a respective first line and energized upon transfer of an associated line interconnection relay, each signal relay, when transferred, energizing the associated operators line connection relay.

5. In a cordless telephone switchboard as claimed in claim 4, each of said signal relays being energized also upon transfer ofthe associated operators line connecting relay; and an all first lines busy signal having an energizing circuit controlled by all of said signal relays and completed only when all of said signal relays are transferred.

6. In a cordless telephone switchboard for interconnecting selected first lines to selected second lines, and including an operators line; a plurality of self locking operators line connecting relays each operable when energized, to connect a respective associated first line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated first line to its associated second line; normally open first push button switches each associated with a different first line and each effective, when selectively momentarily manually closed, to energize the associated operators line connection relay; normally open second push button switches each associated with a different second line and each effective, when selectively momentarily manually closed, to energize the particular associated line interconnection relay associated with a first line then having its associated operators line connection relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connecting relays and energized immediately upon closure of a first push button switch, to open said locking circuits; an extension telephone connected directly to one or" said second lines; a busy signal lamp for said one second line; a relay connected to said one second line and to switch means closed when said extension telephone is in use, and transferred upon closure of said switch means; and an energizing circuit for said busy signal lamp closed upon transfer of said last-named relay and closure of the second push button switch associated with said one second line.

7. In a cordless telephone switchboard as claimed in claim 6, including switch means selectively Voperable to 1connect said extension telephone to another of said second mes.

8. In a cordless tele-phone switchboard for interconnecting selected rst lines to selected second lines, and including an operators line; a plurality of self locking operators line connecting relays each operable when energized, to connect a respective associated first line to said operators line; a plurality of self locking line interconnection relays equal in number to the total connection points between said first lines and said second lines and each operable, when energized, to connect its associated first line to its associated second line; normally open first push button switches each associated with a different first line and each effective, when selectively momentarily manually closed, to energize the associated first hold relay; normally open second push button switches each associated with a different second line and each effective, when selectively momentarily manually closed, to energize the particular associated line interconnection relay associated with a first line then having its associated operators line connecting relay energized; a quick transfer relay in said operators line controlling the locking circuits of said operators line connecting relays` and energized immediately upon closure of a rst push button switch, to open said locking circuit; a plurality of signal relays each energized upon transfer of an associated line interconnection relay; a plurality of fourth relays each energized upon transfer of an associated signal relay; a plurality of iifth slow restore relays each energized upon transfer of an associated fourth relay; and plurality of sixth relays each having an energizing circuit including, in series, a restored contact of the associated fourth relay and a transferred contact of the associated fifth relay; whereby each sixth relay is restored after a time delay following restoring of the associated fourth relay resulting from restoration of the associated third relay; each sixth relay, when transferred, completing the locking circuit of the associated line interconnection relay associated with each third relay.

9. Ina cordless telephone switchboard as claimed in claim 3, a transistorized audio oscillator; and an energizing,

10. In a cordless telephone switchboard as claimed inY claim 1, in which the push buttons of said switches are translucent; and respective colored-1amp 4means in each push button energized Vresponsive to closure of the associated hold relay; said push buttons being readily manually displaceable for access to said lamp means.

References Cited in the lile of this patent UNITED STATES PATENTS 2,226,725

Klenk Dec. 31, 1940' 

1. IN A CORDLESS TELEPHONE SWITCHBOARD FOR INTERCONNECTING SELECTED FIRST LINES TO SELECTED SECOND LINES, AND INCLUDING AN OPERATOR''S LINE; A PLURALITY OF SELF LOCKING OPERATORS''S LINE CONNECTING RELAYS EACH OPERABLE WHEN ENERGIZED, TO CONNECT A RESPECTIVE ASSOCIATED FIRST LINE TO SAID OPERATOR''S LINE; A PLURALITY OF SELF LOCKING LINE INTERCONNECTION RELAYS EQUAL IN NUMBER TO THE TOTAL CONNECTION POINTS BETWEEN SAID FIRST LINES AND SAID SECOND LINES AND EACH OPERABLE, WHEN ENERGIZD, TO CONNECT ITS ASSOCIATED FIRST LINE TO ITS ASSOCATED SECOND LINE; NORMALLY OPEN FIRST PUSH BUTTON SWITCHS EACH ASSOCIATED WITH A DIFFERENT FIRST LINE AND EACH EFFECTIVE, WHEN SELECTIVELY MOMENTARILY MANUALLY CLOSED, TO ENERGIZE THE ASSOCIATED OPERTORS''S LINE CONNECTION RELAY; NORMALLY OPEN SECOND PUSH BUTTON SWITCHES EACH ASSOCIATED WITH A DIFFERENT SECOND LINE AND EACH EFFECTIVE, WHEN SELECTIVELY MOMENTARILY MANUALLY CLOSED, TO ENERGIZE THE PARTICULAR ASSOCIATED SECOND HOLD RELAY ASSOCIATED WITH A FIRST LINE THEN HAVING ITS ASSOCIATED FIRST HOLD RELAY ENERGIZED; A QUICK TRANSFER RELAY IN SAID OPERATOR''S LINE CONTROLLING THE LOCKING CIRCUITS OF SAID OPERATOR''S LINE CONNECTING RELAY AND ENERGIZED IMMEDIATELY UPON CLOSURE OF A FIRST PUSH BUTTON SWITCH,TO OPEN 